Device for forming lines of weakness in sheet packaging material



D. HEYER Oct. 19,- 1965 DEVICE FOR FORMING LINES 0F WEAKNESS IN SHEET PACKAGING MATERIAL Filed July 30, 1962 INVENTOR. (DO/V H5758 621a. (aw

United States Patent 3,212,381 DEVICE FOR FORMING LINES (BF WEAKNESS IN SHEET PACKAGING MATERIAL Don Heyer, 1012 N. Norman Place, Fullerton, Calif. Filed July 30, 1962, Ser. No. 213,468 6 Claims. ((11. 83308) The present invention relates to a device for forming lines of weakness as tear lines in sheet packaging material.

It is the present popular practice to machine pack various articles of merchandise in bags and similar packages made of strips or sheets of flexible, tough and us ally transparent plastic material. In view of the toughness of the bags or similar packages and the fact that they are usually sealed about their margins, the opening thereof is often a difficult and time consuming operation requiring in many instances that the bag be slit or cut to gain access to the contents thereof.

It is an object of the present invention to provide a novel and simply constructed device for forming lines of weakness or tear lines in packaging material preliminary to the material being formed into bags or like packages whereby such bags or packages may be easily opened.

The above objective is accomplished in accordance with this invention by providing novel means for perforating and thereby forming lines of weakness or tear lines in sheet packaging material while the latter is in roll form and preliminary to the formation of the material into bags or similar packages, the perforating means being operated as the roll is rotated in response to unwinding the material therefrom.

It is another object of this invention to provide a device of the character described which is constructed and arranged so that it readily may be used in conjunction with a conventional packaging machine for packaging articles in bags and wherein the packaging material is fed from a roll thereof into the machine, the perforating device operating during the feed of the material to form tear lines which in the finished bags will be located to facilitate ready opening thereof.

It is another object to provide a perforating device such as described wherein a plurality of rotative members are provided with perforating spikes for engaging and penetrating windings of a roll of packaging material at a location inwardly spaced from the point on the roll where the outermost winding leaves the periphery of the roll in being unwound, whereby the perforating spikes will form rows of perforations through a plurality of windings on the roll as the material is being unwound.

It is a further object to provide a perforating device such as above noted having means for urging the spikes in a direction for penetrating wrappings of material on the roll as well as novel means for limiting the depth of this penetration of the perforating spikes into the windings of the sheet material on the roll.

Another object is the provision of a perforating device such as described wherein the rotative perforating members are adjustably mounted in a manner making it possible to form lines of weakness or tear lines at various 1ocations with respect to the side edges or margins of the sheet material, so that when the perforated material is formed into bags or packages the lines of weakness will be located in a position best suited for an easy opening of a bag or package of particular shape and size.

3,212,381 Patented Oct. 19, 1965 ice Other objects and advantages of the invention will be hereinafter described, or will become apparent to those skilled in the art to which the invention appertains, and the novel features thereof will be defined in the appended claims.

Referring to the drawings:

FIG. 1 is a side elevation partly in section of a perforating device embodying the present invention as it would appear when operatively connected with a packaging machine, part of which is schematically shown,

FIG. 2 is an enlarged fragmentary sectional view taken on the line 2-2 of FIG. 1,

FIG. 3 is a fragmentary front elevational view of the device as shown in FIG. 1,

FIG. 4 is an enlarged fragmentary sectional view taken on the line 44 of FIG. 3,

FIG. 5 is a sectional view on the line 5-5 of FIG. 2; and

FIG. 6 is a perspective View of a bag having tear lines formed by the perforating device and showing how the bag may be torn open on the tear lines.

Referring more specifically to the drawings, A designates a perforating device embodying the present invention as it would appear when operatively connected with a packaging machine B shown in part schematically in FIG. 1. As here shown, the machine B includes a frame 7 on which is mounted a roll 8 of sheet packaging material 9 and a combined packaging and bag forming unit 10 to which latter the material 9 is fed with the aid of a guide roller 11 on the frame. The unit It? includes a feed chute 12 through which articles to be packaged are deposited in a bag that is formed as indicated at 13 in the unit 10 from the packaging material 9 fed thereto. Since the packaging machine forms no part of this invention, further illustration thereof is deemed unnecessary and it is to be understood that the perforating device of this invention may be operaed with any packaging machine for forming bags, packages and the like from a roll of packaging material similar to that here shown.

The perforating device as here shown is operable to form tear lines or lines of weakness, for example, as indicated in FIG. 3, in the packaging material so that when the bags are formed these lines will be positioned in the bags to facilitate an easy tearing of the bag to give access to the contents thereof. A typical finished bag designated 14 is shown in FIG. 6 with tear lines 15 extending longitudinally between the sealed margins thereof, the bag being torn along portions of the lines 15 to illustrate one method of opening the bag.

In accordance with this invention perforating means are provided in the device A in the form of a plurality of rotative perforating members 17 arranged on a suitably supported rotatable shaft 18 so as to engage the outer wrapping of packaging material on the upper side of the roll 8 at a location which, as shown in FIG. 1, is spaced rearwardly from that portion of the periphery of the roll where the material leaves the roll in being unwound therefrom.

Each perforating member 17 includes a circular body 19 surrounding the shaft 18 and having a series of perforating spikes 2G radiating therefrom so as to perforate the material 9 as the roll revolves in unwinding the material therefrom. Each spike 20, as here shown, is larger at its base and tapers to a point to assure desired perforation of wrapping of the material on the roll 8.

Each body 19 is mounted between a pair of circular disks 21 and 22 surrounding the shaft 18 with the peripheries of the disks being spaced inwardly from the outer ends of the spikes so as to engage the roll 8 and limit the penetration of the spikes into the windings of the material on the roll 8. The disk 21 has an integral tubular hub 23 of non-circular cross section on the exterior thereof and which extends laterally through a noncircular Opening 24 in the body 19 of the perforating member 17, as well as through a similar opening 24' in the disk 22 to support the latter. Each disk 22 is provided with a set screw 25 engageable with the shaft 18 to fix the perforating member 17 as a unit to the shaft for rotation therewith. With this arrangement the several perforating members may be axially adjusted on the shaft 18 and then set by means of the set screws 25, so as to be spaced as desired to form the spaced rows of perforations defining the lines of Weakness at selected locations, for example, as shown in FIG. 3. This location of the rows of perforations is determined according to the shape and size of the bags and packages that are to be formed with the material 9.

As here shown, the shaft 18 is supported so that it will gravitationally move downwardly to engage the top of the roll 8 whereby it will follow this roll as the diameter thereof decreases in unwinding the packaging material therefrom.

Suitable means may be employed in connection with the support means for the shaft 18 to urge the perforating members forcibly against the roll in order to penetrate simultaneously a number of the windings on the roll. As here shown, the shaft 18 is supported centrally of its ends in a bearing block 26 carried by the outer end of an arm 27 projecting from a shaft 28 on the frame 7. Collars 29 are mounted against opposite sides of the bearing 26 and are secured to the shaft 18 by set screws 30 to prevent axial shifting of the shaft 18 relative to the bearing 26. With this arrangement the shaft may be adjusted axially relative to the bearing and fixed in adjusted position by tightening the set screws 30 with the collars against opposite sides of the bearing. The shaft 28 may be rotatably mounted in the frame 7 or the arm 27 extending from the shaft arranged to swivel on the latter. As here shown, however, a connecting block 31 is mounted on the shaft 28 which is suitably supported at its ends in bearings 28' on the frame 7, the block being fixed to the shaft by means of a set screw 32 so that the arm 27 and the perforating unit as a whole may swing downwardly freely onto the top of the roll 8 as the shaft turns.

Suitable means may be used to urge the perforating members downwardly onto the roll 8. As here shown, an arm 33 extending outwardly from the block 26 has an axially adjustable weight 34 mounted thereon so as to urge the perforating member 17 forcibly downwardly against the roll 8. A screw fastening 35 is slidable in a slot 36 in the arm 33 and threaded into the weight 34 whereby the latter may be adjusted on the arm to regulate the force at which the perforating members are urged downwardly against the roll 8.

In the operation of the perforating device following the positioning thereof as shown in FIGS. 1 and 2 so that the spiked perforating members 17 bear downwardly upon the upper side of the roll 8 of packaging material 9, when the latter is unrolled, the roll will turn and thereby cause the spiked members 17 to rotate and penetrate a plurality of windings of the material. This rotation of the members 17 and the weight of the device including the weight 34, cause spikes 20 to bite into the roll and penetrate a number of the windings, the depth of penetration being limited by the disks 21 and 22 contacting the roll as shown in FIG. 2. Consequently as the material is unwound it will have a considerable length thereof formed with the rows of perforations which form tear lines that will be located at joints in bags or packages made of the material, to facilitate the quick tearing open of such bags or packages.

As the perforating device gravitationally swings downwardly to follow the roll as the diameter thereof decreases, the perforations will be formed throughout the entire length of material stored on the roll.

It should be noted that in view of the simple construction of the perforating device, any support therefor may be used which will permit the device to swing down onto the top of a roll of sheet material in which it is desired to form perforations as lines of weakness or tear lines. Accordingly, it will be apparent that the device readily lends itself to use with various types of packaging machines or other devices wherein a roll of sheet material is used and it is desired to form one or more rows of perforations in the sheet material as the same is unwound from the roll.

I claim:

1. A device for perforating and thereby forming tear lines in sheet material in roll form mounted to rotate as the material is unwound therefrom comprising: a rotary perforating member having perforating spikes thereon; and support means mounting said rotary perforating member for continuous movement toward the axis of the roll and maintaining said spikes in a position penetrating a number of windings on the roll and for effecting continuous penetration of additional windings on said roll in response to unwinding of said material from said roll.

2. A device for forming tear lines in a roll of sheet material mounted to rotate as the material is unwound therefrom comprising: a rotary perforating member having perforating spikes thereon; support means mounting said rotary perforating member for movement toward said roll to engage said spikes with and penetrate a number of the windings on said roll so that said perforating member will rotate in response to rotation of the roll upon unwinding of the material; and means urging said perforating member bodily and continuously toward the axis of said roll to cause said spikes to perforate a plurality of additional windings on said roll during further rotation of said perforating member.

3. A device as specified in claim 1 including means associated with said perforating member for limiting penetration of said spikes into said material on said roll.

4. A device for perforating and thereby forming tear lines in sheet material in the form of a roll mounted to rotate as the material is unwound therefrom, comprising: support means movable toward said roll; a plurality of rotary perforating members mounted on said support means; each of said perforating members having spikes thereon; and said support means including a shaft on which said perforating members are axially spaced with said spikes engageable with said material so thatsaid perforating members will rotate and cause said spikes to penetrate windings of material on the roll upon the unwinding of the material from said roll; said support means and said shaft being movable as a unit continuously to effect movement of said perforating member toward the axis of said roll with said spikes penetrating a plurality of said windings during the unwinding of said material from said roll.

5. A device as specified in claim 4 including means axially adjustably mounting said shaft on said support means and means for fixing said shaft in axially adjusted positions.

6. A device for perforating and thereby forming tear lines on sheet material in the form of a roll mounted to rotate as the material is unwound therefrom comprising: a support; a first shaft on said support; an arm extending from said first shaft and movable toward said roll; a second shaft carried by said arm; a plurality of rotary perforating members on said second shaft; and each of said perforating members having spikes extending radially 5 6 therefrom and disposed to continuously move inwardly 1,545,634 7/25 Bird 83105 toward the axis of said roll and penetrate a plurality of 1,998,357 4/35 Carlson 83-425 windings of said material as the roll revolves and becomes 2,388,069 10/45 Meaker et a1 83308 reduced in diameter during unwinding the material there- 2,710,060 6/55 Birkmann 83-649 from. 5 3,021,732 2/62 Schur 76101 3,074,303 1/63 Waters 83660 References Cited by the Examiner UNITED STATES PATENTS 934,397 9/09 Fellows 83348 1,124,402 1/15 Eldot et a1 101-213 10 ANDREW R. JUHASZ, Primary Examiner.

HUNTER BOURNE, JR., LEON PEAR, Examiners. 

1. A DEVICE FOR PERFORATING AND THEREBY FORMING TEAR LINES IN SHEET MATERIAL IN ROLL FORM MOUNTED TO ROTATE AS THE MATERIAL IS UNWOUND THEREFROM COMPRISING: A ROTARY PERFORATING MEMBER HAVING PERFORATING SPIKES THEREON; AND SUPPORT MEANS MOUNTING SAID ROTARY PERFORATING MEMBER FOR CONTINUOUS MOVEMENT TOWARD THE AXIS OF THE ROLL AND MAINTAINING SAID SPIKES IN A POSITION PENETRATING A NUMBER OF WINDINGS ON THE ROLL AND FOR EFFECTING CONTINUOUS PENETRATION OF ADDITIONAL WINDINGS ON SAID ROLL IN RESPONSE TO UNWINDING OF SAID MATERIAL FROM SAID ROLL. 